It needs to be noted that people respond to PEDs differently. Some get more out of them than others, there is not one clear way to show if one lifter is using and other don't.
This whole steroid thing is pretty complex and difficult subject. Judging and banning is just naive and causes more problems than fixes (similar topic to guns, drugs, prostitution and all the other vices people have). I understand that natural lifter feels frustrated because someone has benefits that he/she has not, but we must remember that steroids aren't everything. "Well, he uses" is the most lame excuse to downplay someones success in sport. With the same logic we could downplay someone since he/she has good leverages and genetics (Michael Phelps as an example).